#!/bin/bash

function s1_read_last_two_bytes_of_a_mbr_backup_file(){
        local mbr_backup="$1"
        local last_bytes=$(tail -c 2 "$file_path" | od -A -t x1 | tr -d '\n')
        if [[" $last_bytes" == "55AA"]]; then
             echo YES
        else 
             echo NO
        fi
}

function s2_read_mbr_partition_table_info(){
         echo -n 'echo"ibase=16;800" | bc'
         echo -n ' '
         local mbr_backup_file=$1
         for i in {0..3};do
         local offset=$((446 + i * 16))
         local partition_entry=$(od -j $offset -N 16 -t x1 -An "$mbr_backup_file" | tr -d '\n')
         local partition_type=$(echo $partition_entry | cut -c 9-10) 
         if [ "$partiton_type" != "00" ]; then
         local start_sector_hex=$(echo $partition_entry | cut -c 17-24 | tr '[:lower]' '[:upper]')
         local start_sector=$(echo "ibase=16;$start_sector_hex" | bc)
         local end_sector_size_hex=$(echo $partition_entry | cut -c 33-40 | tr '[:lower:]' '[:upper:]')
         local ecd_sector_size=$(echo "ibase=16;$end_sector_size_hex" | bc)
         local end_sector=$((start_sector+end_sector_size - 1))
         if [$i -eq 0 ];then
         echo -n "$end_sector"
         echo -n "$start_sector"
         else
         echo -n "$end_sector"
         fi
         fi
         done
}

function s3_parse_partition_info(){
         fdisk_output=$(cat)
         disk_size_bytes=$(echo "$fdisk_output" | grep "Disk /dev/vda:" | awk '{print $5}')
         disk_size_sectors=$(echo "$fdisk_output" | grep "Disk /dev/vda:" | awk '{print $7}')
         physical_sector_size=$(echo "$fdisk_output" | grep "Sector size" | awk '{print $4}')
         first_partition_start_sector=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $3}')
         first_partition_end_sector=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $4}')
         first_partition_type=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $8}')
         echo "disk size in bytes:$disk_size_bytes"
         echo "disk size in sectors:$disk_size_sectors"
         echo "physical sector size in bytes:$physical_sector_size"
         echo "first partition start sector id:$first_partition_start_sector"
         echo "first partition end sector id:$first_partiton_end_sector"
         echo "first partition type:$first_partiton_type"
         

}

function s4_run_passwd_as_plain_user_and_get_status(){
         oversleeping_path=$(which oversleeping)
         chown root "$oversleeping_path"
         chmod 755 "$oversleeping_path"
         $oversleeping_path & ps -o uid,euid,ruid -C 'oversleeping' | awk 'NR>1 {print $1","$2","$3}'
}

function s5_add_a_scheduled_task(){
        (crontab -l 2>/dev/null; echo "*/5 * * * * echo \$(date +'%Y%m%d_%H%M%S') >> \$HOME/test_crontab") | crontab
}
